The present invention relates to a new and improved construction of a gear cutting machine of the type comprising a tool rotating about a first axis, this first axis being pivotable about a second axis along a first cone-shaped shell or cone, the second axis being pivotable about a second cone-shaped shell or cone about a third axis, there further being provided a gear drive possessing two pairs of bevel gears, the first axis being operatively connected by means of the gear drive via the second axis with the third axis.
A gear cutting machine of this type has been disclosed in U.S. Pat. No. 2,792,764, granted May 21, 1957 and corresponding to German patent 924,303, published Feb. 28, 1955, the disclosure of which is incorporated herein by reference, wherein the axis of rotation of the tool likewise is pivotable at an imaginary cone-shaped shell or cone about a second axis. This pivotal movement occurs by rotating a support body or carrier in a head. The second axis is likewise pivotable at a second cone-shaped shell or cone about a third axis, this pivotal motion occurring by adjusting the head in a headstock. The first axis is connected via the second axis with the third axis through the ageny of a gear drive. The gear drive possesses two pairs of bevel gears. One pair of bevel gears consists of bevel gears possessing an obtuse-angle cone apex, the other pair of bevel gears consists of bevel gears possessing an acute-angle cone apex. A drawback of this prior art apparatus resides in the fact that the fabrication and assembly of the gear drive is complicated and expensive, since two different pairs of bevel gears are employed. Furthermore, a large checking machine is necessary in order to check the acute-angle bevel gears. The acute-angle bevel gears incorporate fewer teeth which are simultaneously in running mesh than the obtuse-angle bevel gears, so there is present a poorer meshing of both bevel gears and the longevity of the gears is markedly reduced.